The present invention relates to a medium feeding apparatus provided in an image forming apparatus or the like.
In an image forming apparatus such as a copier, a printer, a facsimile or the like, an exposure unit such as a laser scanning unit or an LED (light emitting diode) emits light to expose a surface of a photosensitive body (i.e., an image bearing body) based on a image data to form a latent image. The latent image is developed with toner. The resulting toner image is transferred directly or via an intermediate transfer body to a medium such as a printing sheet or a film. The medium is conveyed to a fixing unit, where the toner image is fixed to the medium by application of heat and pressure.
Such an image forming apparatus includes a medium feeding apparatus for storing and feeding the medium. The medium feeding apparatus has a medium cassette in which a stack of the media (i.e., printing sheets) is stored. The medium cassette is detachably mounted to a main body of the medium feeding apparatus. The medium cassette has a pair of medium guides that determine positions of both ends of the media in a widthwise direction. Both medium guides have guide racks that engage a common pinion gear (see, for example, Japanese Laid-open Patent Publication No. 2008-81259 (FIG. 1)).
In this regard, when the medium cassette is mounted to the main body of the medium feeding apparatus, there is a possibility that the medium guides may be unintentionally displaced. In such a case, the medium (guided by the medium guides) may also be displaced.